Phase behaviors of polymer solutions using molecular simulation technique

Abstract

Phase behaviors of polymer solutions are estimated using a combination of thermodynamic models and molecular simulation technique. In general, many parameters of binary systems are determined by fitting a thermodynamic model with experimental data. In this study, we obtained all parameters using molecular simulation. To take the specific interaction into account, we assume that it only occurs between a solvent molecule and a specific group. Our results show that the theoretical treatment accounting for the specific interaction gives more accurate predictions than those without consideration of specific interaction. Also, our approach describes the phase equilibria of various polymer solutions over the entire concentration remarkably well.

Predicting the proton conductivity of perfluorosulfonic acid membrane via combining statistical thermodynamics and molecular dynamics simulation

“…In addition, the specific interaction such as hydrogen bond is also listed. The calculation method for specific ε and δε is obtained from Yang and Bae's work for chemical activity calculation using molecular simulation 21. These parameters are reduced by Boltzmann constant and temperature and adapted to Eqn.…”

“…From this method, three Boltzmann‐averaged pair wise interaction energy values (ε 11 , ε 12 , and ε 22 ) for each model segment were obtained. We calculated the mixing energy of each solvent molecule with polymer repeat units 21…”

“…If the oxygen group in perfluorosulfonic acid membrane interacts with water molecules, it often results in hydrogen bonding. It should be precisely calculated with the particular oxygen group and solvent 21. We considered polymer solutions where segment‐segment interactions between i and j include oriented interactions originating from hydrogen‐bonding, donor‐acceptor electron transfer or strong dipole‐dipole interactions.…”

“…To calculate the specific interaction energy from the simulation results, we assume that a specific interaction only occurs between a solvent molecule and specific group in the polymer repeat unit. The specific calculation method was obtained from Yang et al21…”

Phase Equilibrium Calculations of Ternary Liquid Mixtures with Binary Interaction Parameters and Molecular Size Parameters Determined from Molecular Dynamics

“…The method presented here is based on a molecular dynamics simulation, an established method of research in this area and a useful tool in solving the above-mentioned problem. , In our method, molecular size and binary interaction energy parameters, fundamental parameters in thermodynamic models, are determined by molecular simulation and, therefore, correlating work is not required. The LLEs of ternary liquid mixtures were predicted by using three lattice models (FH, LCT, MDL).…”